Treatment of iron sulphide-bearing material



July l1, 1933. R. F. BACON ET AL 1,917,233

TREATMENT 0F IRON SULPHIDE BEARING MATERIAL Filed Feb. ze, 195o BY m,

ATTORN EYS Patented July 11, 41933 RAYMOND F. BACON, or BRONXVILLE, AND

PATENT i OFFICE `IIEl-NRY T. HOTGHKISS, JR., OF NEW l ROCHELLE'NEW YORK;vv SAID HOTCHKISS, JR., ASSEGNOR TOl SAID BACON TREATMENTOF IRON SULIPHIDE-BEARNG MATERAL Application filed February 26, 1930. Serial No. 431,472.

This invention relates tothe recovery'of sulphur and has for an obj eet thek provision of an improved processfor recovering sulphur from heavy metal sulphide ores. More particularly, the invention contemplates the provision of an improved process for recoverinO' sulphur from materials containing one or more sulphides of iron. The invention further contemplates the provision of an iinproved process Jfor treating heavy metal sulphide ores such,or example, as ore containing sulphides of iron, copper and nickel.

The process of the present invention involves the treatment of ore or other metallurgical raw materials or products containing pyrites or other sulphides of iron, alone or in combination with sulphides of other lheavy metals such, for example, as copper and nickel, with sulphuryl chloride Jfor the purpose of obtaining free sulphur and/or separating iron from the mass of material undergoing treatment. f K

ln carrying out a process in accordance with the present invention, a quantity of the material to be treated is subjected to the action ont sulphuryl chloride under such condi tions that free sulphur and ferrie chloride are produced and vaporized. The vaporiZed sulphur' is collected and the free chloride is utilized for treating additional quantities of sulphide-bearing material to produce a product in which ferrous chloride is concentrated. The ferrous chloride concentrate is appropriately treated to recover chlorine which is returned to the process.

The process may be conveniently conducted by passing the sulphide-bearing material progressively through reaction Zones of different temperatures. According to the preferred process of the invention, the iron sulphide-bearing material is first introduced into a reaction Zone oi relatively high temperature and passed progressively through reaction zones of lower temperatures. The

process is so controlled that ferrous chloride is produced in the high temperature'reaction Zones and lower temperature reaction Zones. Elemental sulphur is produced and vaporized and the ferrie chloride produced is vaporized. The vaporized sulphur and ferrie chloride Vare caused to pass over fresh or partially converted sulphide-bearing material in the higher temperature reaction Zones,-the sulphur vapor ultimately being collected as free sulferric chloride is producedin the phur, and the lferrie chloride reacting with sulphide compounds and being reduced to ferrous chloride.

During the course oi the reaction between the sulphuryl chloride and the sulphides contained in the materialy being treated, sulphur dioxide gas is Vtormed and passes out 'of the reaction chamber withv the vaporized sulphur.

The recovered chlorine is combined with the sulphur dioxide produced to regenerate sulphuryl chloride vwhich is returnedV to the process.

' The process may be carriedv out in any suitabletype lof apparatus, but it is preferably "carried out in a rotary reaction chamber in which a suitable temperature gradient ismaintained and into which the sulphuryl chloride and iron sulphide-bearing material are introduced at appropriate points.

The-invention will be better understood ironia consideration of the accompanying flowsheet and the following description of a process involving the treatment ot' ore containing `pyrites and sulphides of copper and nickel.

The ore to be treated is introduced in a d ry, linelyvr divided condition into the interior charging means at one end and discharging means at the other end. An opening or passage to permit the outward passage of sulphur vapors and other gases is provided 'near the charging end.

' The reaction between the sulphuryl chloride and heavy metal sulphides starts at a temperature of about 250O C. and proceeds most rapidly at a temperature of about 5000 C. to 550 C. Itis, therefore, advisable tomaintain a temperature yof about 500 C. to 550O C. in at least a portion of the reaction chamber. Such a temperature may be maintained near the charging end portion of the reaction chamber to insure the Vpassage of all issuing gases through a zone in .which conditions are conducive to a complete reaction.

' The :temperature within the reaction chamber is prefer-ably so` regulated thatA it gradually increases from the normal atmospheric temperature at 'the' charging end to a maximum temperature ofabout 55()O C at a point about midway between the charging end and the longitudinal center of the reaction chamber, and gradually decreases fromv the region of maximum temperature to ,about ot a'rotary reactionl chamber having- 300 C. at the dischargeend. The opening or passage for sulphur vapors is preferably located at a point between the charging end of the chamber and the region of maximumV temperature where 'the temperatureY within the chamber is about 450 C. or slightly lower.

The ore, preferably ground to provide particles sufficiently small to pass a 10U-mesh screen in order that intimate contact of the sulphuryl chloride with the sulphide compounds may be obtained, is introduced into the reaction chamber at thecharging end. Sulphuryl chloride is introduced into the reaction chamber at the discharge end. The sulphuryl chloride may be introduced into the reaction chamber as a liquid or as a gas. Liquid sulphuryl chloride will be vaporized immediately after its introduction.

The process is conducted as a batch process, the discharge end of the chamber being closed. The ore may be fed to the chamber continuously until the desired concentration has been effected, or the ore may be fed to the reaction chamber until a predetermined amount has been introduced.

When ore is first introduced into the reaction chamber, no sulphuryl chloride is introduced until the ore yreaches or passes the zone of maximum temperature. As-the ore reaches the Zone of maximum temperature, the sulphuryl chloride may be admitted, slowly at first, and in gradually increasing amounts as the ore and chlorinated material progress through the chamber. Sulphuryl chloride may be admitted at anydesired maximum rate. lThe rate at which sul* phuryl chloride is admitted and the amount ofsulphuryl chloride admitted will be determined by the rate of feeding of ore into the reaction Zonesand the amount of ore to be treated.

During the course of the process, the sulphuryl chloride first reactsvwith the sulphides of iron, copper and nickel to produce sulphur dioxide, free sulphur, ferrous chloride and the chlorides of copper and nickel. lThe free sulphur is vaporized and passes out of the reaction chamber with the sulphur dioxide to suitable collecting and condensing apparatus. As the reaction chamber is rotated, the ferrous chloride-bearing material moves gradually toward the discharge end and fresh ore is moved into the zone of maximum temperature. As the ferrous chloride-bearing material moves toward the discharge end the sulphuryl chloride reacts with the ferrous chloride and oxidizes it to ferrie chloride. The ferrie chloride produced is vaporized and the resulting vapor is swept along with the sulphuryl chloride toward the Zone of maximum temperature. The ferric chloride comes into contact with i fresh or partially chlorinated sulphide-bearing material and is reduced to ferrous chlocentrated in the Aadjoining portion of the re# action chamber;

The? material in the discharge end portion of the reaction chamber will consist substantially entirely of nickel and copper vchlorides and gangue materials which may be present in the original orefr l/Vhenthe ore isv fed continuously during the course of a process, the admissionv of ore and sulphuryl chloride 'may be discontinued when the presence of considerable ferrie chloride `in the issuing sulphurvapor indi- Cates that insufhcient fresh ore is beingmcved inte the reaction zones to react with the ferric chlorideV produced, or when the operations have been conducted for Va predetermined length of time. .y

Vlhenthe ore is'fed to the reaction chamber only until a predetermined amount has been admitted, the admission of sulphuryl chloride may be discontinued when the Vlast portion of the ore reaches the Zonevof'maximum temperature. The process.'l may be so vconducted `that ysatisfactory concentration w'll Vhave been effected at that time.

in the case of continuous feeding, at the completion of the chlorination treatment,

the iron-free material containing chlorides of copper and nickel will be segregated in the discharge end portion of the chamber, fresh or substantially unaltered ore will be present in the portion of the reaction chamber between theV charging end and the zone of maximum temperature, and the ferrous chloride-bearing material will be concentrated inthe intermediate portion of the reaction chamber. Y

Upon the completion of a. chlorination process involving the admission of a predetermined amount of o're, the iron-'free material will be segregated inthe discharge end portion ef the reaction chamber, and the ferrous chloride-hearing.material Vwill be cencentrated in the adjoining portion of the chamber.V The charging end portion yof the chamber will be empty.

When the admission of sulphuryl chloride has been discontinued, the discharge end cf the reaction chamber may be opened. Rotation of the reaction chamber will cause the contents to be discharged. .The iron-free material containing chlorides of copper and fisc' '"5 immediately.

I1 rides.

Concentrate is discharged and collected separately.

lWhen the ferrous chloride concentrate has been discharged, treatment of a fresh batch of ore is commenced.

The ferrous chloride concentrate is subjected to the action of air at a temperature of 700 C. to SOOo C. to recover' chlorine. The treatment of the ferrous chloride concentrate is preferably so conducted that free chlorine is produced.

The chlorine recovered is combined with the sulphur dioxide produced to regenerate sulphuryl chloride. The reaction between the sulphur dioxide and the free chlorine is preferably conducted at or below normal atmospheric temperatures in the presence of a suitable catalyst such, for example, as activated charcoal. rlhe regenerated sulpliuryl chloride may thus be obtained in the form of a liquid. The regenerated sulphuryl chloride is utilized for the treatment of the fresh batch of ore.

its a result of the treatment of the ferrous chloride-bearing material. with air, considerable quantities of inert gases such as nitrogen are introduced into the system and must be eliminated to avoid excessive dilution. The inert gases introduced into the system will l be mixed with the chlorine gas which is recovered and which is combined with the sulphur dioxide produced to regenerate sulphuryl chloride. These gases will be eliminated as a result of the production of liquid sulphuryl chloride. The inert gases may be passed through a suitablev separator to recover entrained particles or globules of sulphuryl chloride.

The treatment of a batch of ore with sulphuryl chloride and the treatment of a ferrous chloride-bearing residue for the recovery of chlorine are preferably conducted simultaneously in order that the sulphur dioxide and chlorine produced may be utilized A fresh source of chlorine, in the free state or combined in the form of sulphuryl chloride, may be provided to compensate forl chlorine losses due to leakage and the production of niclel'and copper' chloln the event that a source of free chlorine is provided, an additional source of sul ihur dioxidemust be provided.

wWe claim:

l. ln a process for treating iron sulphidebearing material involving the treatment of the material in the presence of a chlorinating agent, the improvement which comprises subjecting the material to progressively decreasing` temperatures in the presence of sulphuryl '3: chloride.

2. The method of treating iron sulphidebearing material which comprises subjecting the material in a reaction chamber to the action of sulphuryl chloride to produce ferrous chloride, oxidizing the ferrous chloride to recover chlorine, converting the chlorine to sulphuryl chloride, and returning the sulphuryl chloride thus recovered to the process.

3. The method of treating iron sulphidebearing material which comprises subjecting the material in a reaction chamber to the action of sulphuryl chloride to produce ferrous chloride, sulphur dioxide and elemental sulphur, subjecting the ferrous chloride to the action of air at an elevated temperature to recover chlorine, combining the chlorine recovered with the sulphur dioxide produced to regenerate sulphuryl chloride, and returning the sulphuryl chloride thus recovered to the process. v

4l. The method of treating ore containing sulphides of iron and copper which comprises subjecting the ore to the action of sulphuryl chloride at an elevated temperature to form and vaporize ferrie chloride and obtain a substantially iron-free product containing copper chloride and elemental sulphur.

5. rlhe method of treating ore containing pyrites and a non-ferrous metal sulphide which comprises subjecting the ore to the action of sulphuryl chloride to form and vaporize ferrie chloride and elemental sulphur and obtain a substantially iron-free product containing a non-ferrous metal chloride.

6. The method of treating ore containing pyrites and sulphides of copper and nickel which comprises subjecting the ore to the action of sulphuryl chloride to form `and vaporize ferrie chloride and elemental sulphur and obtain a substantially iron-free product containing copper and nickel chlorides.

7. The method of treating iron sulphidebearing material which comprises subjecting one portion of the material in a reaction chamber to the action of sulphuryl chloride to produce ferrous chloride, sulphur dioxide and elemental sulphur, chlorinating the ferrous chloride to ferrie chloride while maintaining a temperature suitable to vaporize the ferric chloride, contacting the ferrie chloride so produced with another portionk of said materialin the chamber to chlorinate the same and form a ferrous chloride concentrate, oxidizing the ferrous chloride concentrate to recover chlorine, combining the chlorine recovered with the sulphur dioxide produced to regenerate sulphuryl chloride, and returning the regenerated sulphuryl chloride to the process.

8. In a process for treat-ing iron sulphidebearing material involving the treatment of the material with a chlorinating` agent, the step which comprises contacting the material with sulphuryl chloride.

In testimony whereof we'affix our signatures.

RAYMOND F. BACON. HENRY T. HOTCHKISS, JR. 

